BLF Interest List: EX3 High Current Beryllium Copper Silver Plated springs - Still selling my springs :)

I’m down for 10SST-20 4000k 95CRI FD2

Sent request to be able to edit the spreadsheet.

Or just add 30 x SST20 FD2 to the spreadsheet for me.

Thanks for making this possible!

Put me down for 18 x SST-20 FD2 please.

Are the rosy 3000K’s available btw?

im in for 15 x SST-20

Add to my 10 FD2 (line 13 in new list) 20 large and 20 small 3rd gen springs.

It looks like, according to the chart you posted, the FD2 tint bin actually spans across the BBL, so individual samples may be above or below the BBL.

Clearly that just means people should order extras, both to fill the MOQ faster and so they're more likely to get enough under the BBL ;)

Ok guys, sorry for some of you, but added the shipping.

Also, @Bob_McBob, they are the same LEDs as what maukka’s tested.
So quite a bit better than what we had before, but not FA3 levels of improvement.

@Agro, that’s 0,8mm+0,040mm in this case, since the 20um figure is only in terms of radius, or one side plating.
So, the total plating thickness is 40um.
Also, the nice thing about plating is that it’s like a cold weld if done well. You can treat those as parallel conductors.

Also, here’s how I calculated the improvement:
Let’s take the large BeCu spring with a 25um copper plating(0,050mm total diameter).
Since copper is 2,6 times more conductive than BeCu C17530, it’s a virtual 0,13mm increase in total wire thickness, so a virtual wire thickness of 1,13mm.

By going with the same calculations, the spring would actually become 20–25 more conductive!
That means the resistance would go down from 9mOhms down to 7,5mOhms-7,2mOhms, without losing the good mechanical properties which were sacrificed in the 2nd gen spring by removing a coil.
So, compared to the 1st gen spring with the same mechanical properties, it’s actually a great improvement.
I still wonder why I didn’t think of that the 1st time around…

Anyway, the improvement is quite a bit larger than what you calculated, so that’s nice.
Finally, the last improvement we could do is a gold plating, but I’m going to keep it for the Ultimate spring, since it’s so expensive, especially with a copper undercoating.

All have been added to the list:

We are at 328 SST-20s FD2 LEDs!

Only 162 more to go.

Which direction will the springs be wound?

I got 100 of the 2nd gen springs and my complaint about them is that they’re wound in a way that’s causing them to gouge into the ends of the battery as you tighten down the tail of the light.

Stronger springs will only gouge deeper if they’re wound the same direction. If possible can they be wound the other way or atleast have the small end hooked in sharply in for battery protection?

Yeah, that’s why I’m going with the 1st gen spring design as found in the photo.

I’ve had the same problem, so going back to that 1st gen spring top coil design.

Added back again with some corrections:

I can’t edit the spreadsheet, please add me in for :

5 x large springs 3
5 x small springs 3
10 x budget springs
10 x SST-20

Thank you :)

BlueSwordM, why do you think Gold would be an improvement? I thought Silver was a better conductor than Gold. In what way does Gold improve the spring?

Added to the list:

Again with the mistakes…

@DavidEF, gold would actually be an improvement in contact resistance because of its atomic structure.

That’s a thing I discovered at my new electroplating job: the reason gold is used in contacts is that its contact resistance is extremely low due to its atomic structure allowing a form of cold weld happening, reducing contact resistance by a huge margin.

It’s about as good as a soldered connection, or slightly better at times due to much thinner layer of contact.

This prevents the formation of hotspots, which is very important in small contacts like we have, as this would increase resistance, and therefore heat.

TLDR: In terms of lowest contact resistance:
Absolute best: Gold.
Excellent: Silver
Good: Silver tarnish.
Good: Nickel
Good: Pure copper
Absolute crap: Oxidized copper.

It seems that the biggest difference in our calculations is that you compare pretty much 3.0 to 1.0 while I compare 3.0 and 1.0-like-but-with-3.0-total-thickness.
I think both approaches are right, they just compare different things. :stuck_out_tongue:
With 25 µm plating thickness like you assume the difference would go up to 13%.

Hmm? Why 13%?
The spring is made of BeCu C17530, and the 50um total thickness layer is made of copper, which is 2,6x as more conductivity as BeCu C17530(100% IACS vs 38% IACS).

If I use your values, I get a 13% improvement, but if I use mine, I get an improvement of 25% at best.

Ah! Ok! I get it now. Sorry. I was comparing the improvement to the 1st gen spring, since it only

But alas, I couldn’t increase the wire thickness to 1,15mm, as not only is it not standard, but it would also compromise spring ability, and by being not standard, it would cost even more than the dual thick copper+silver plated spring.

I’m in for-
12)-FD2 SST-20
10)–3rd gen BeCu (L)
10)–3rd gen BeCu (Sm)

Added to the list:

Did you see my test in that thread? I have an email out to Hank to see what tint bin he used for the D18. It seems to be something different than what he advertises in his store as FB4.

Either that or i’m doing something wrong with my tests.